1. Technical Field of the Invention
The present invention relates to a substrate assembly for an electrooptical device, a method for manufacturing the substrate assembly for the electrooptical device, the electrooptical device, and a method for manufacturing the electrooptical device, and, more particularly, to a structure and a manufacturing process technology appropriate for a transflective-type liquid-crystal device.
2. Description of the Related Art
A transflective-type liquid-crystal display panel presenting both a reflective-type display using external light and a transmissive-type display using illumination light such as the one from a backlight is known. The transflective-type liquid-crystal display panel includes a reflective layer which reflects external light into the panel while transmitting illumination light from a backlight or the like. This type of reflective layer includes an aperture (a slit) having a predetermined area at each pixel of a liquid-crystal display panel.
FIG. 13 is a cross-sectional view diagrammatically illustrating a conventional transflective-type liquid-crystal display panel 100. The transflective-type liquid-crystal display panel 100 includes a substrate 101 and a substrate 102, which are mutually bonded together with a sealing member 103 interposed therebetween, and a liquid crystal 104 encapsulated between the substrate 101 and the substrate 102.
A reflective layer 111 having an aperture 111h for each pixel is arranged on the inner surface of the substrate 101. A color filter 112 formed of color layers 112r, 112g, and 112b and a surface protective layer 112p is arranged on the reflective layer 111. Transparent electrodes 113 are formed on the surface of the surface protective layer 112p of the color filter 112.
Meanwhile, transparent electrodes 121 are formed on the inner surface of the substrate 102 and mutually intersect the transparent electrodes 113 on the counter substrate 101. An alignment layer and a hard transparent layer are formed on each of the transparent electrodes 113 on the substrate 101 and the transparent electrodes 121 on the substrate 102, as necessary.
Arranged on the outer surface of the substrate 102 are a retardation film (¼-wave film) 105 and a polarizer 106 in that order from the substrate 102. Also arranged on the outer surface of the substrate 101 are a retardation film (¼-wave film) 107 and a polarizer 108 in that order from the substrate 101.
When being installed in electronic apparatus such as a mobile telephone or a mobile information terminal, the liquid-crystal display panel 100 thus constructed has a backlight 109 mounted therebehind. In the liquid-crystal display panel 100 during daytime or in a room under light conditions, external light travels along a reflective path R, in other words, is transmitted through the liquid crystal 104, is reflected from the reflective layer 111, is transmitted through the liquid crystal 104 again, and exits outwardly. A reflective-type display is thus presented. During nighttime or under dark conditions outdoors, the backlight 109 is switched on. Light passed through the aperture 111h, out of illumination light from the backlight 109, travels along a transmissive path T, specifically, is transmitted through the liquid-crystal display panel 100, and then exits outwardly. A transmissive-type display is thus presented.
However, in the conventional transflective-type liquid-crystal display panel 100, light is transmitted through the color filter 112 twice along the reflective path R. In the transmissive path T, light is transmitted through the color filter 112 only once. The chroma in the transmissive-type display becomes inferior to that in the reflective display. Specifically, the reflective-type display typically tends to suffer from the lack of brightness. To assure brightness in the display, the light transmittance of the color filter 112 needs to be high. A high light transmittance in the transmissive display means insufficient chroma.
Since the number of times by which light is transmitted through the color filter is different between the reflective-type display and the transmissive-type display, the chroma in the transmissive-type display is substantially different from that in the reflective-type display. As a result, the user may feel odd about color tone.
The present invention resolves the above problem, and it is an object of the present invention to provide a color filter which assures both the brightness in the reflective-type display and the chroma in the transmissive-type display when a display device that presents both the transmissive-type display and the reflective-type display. It is another object of the present invention to provide an electrooptical device which assures both the brightness in the reflective-type display and the chroma in the transmissive-type display. It is yet another object to develop a display technique that reduces a difference in chroma between the reflective-type display and the transmissive-type display.